The present invention relates to an input device for controlling and/or selecting objects on a display unit having at least one bending sensor.
Input devices are used for moving, controlling and selecting objects such as a cursor or switch buttons (icons) on the display unit of an electronic device such as a computer or for input of commands. Keyboards are well known for input of character strings and for controlling the cursor by way of arrow keys. In addition, there is the widely used mouse, where a ball is moved over a surface. The position of a cursor is determined from the direction and speed of movement of the ball. In the case of a track ball, a ball is moved by hand and is not moved over a surface as in the case of a mouse. Other input devices include light pens for optical analysis of the position of the light pen on a display unit and joysticks for control by measuring the angle of tilt of a lever.
Three-dimensional pointing devices such as control balls and control gloves are well known for digitizing three-dimensional movements. With such three-dimensional pointing devices, a cursor can be moved in a space displayed in perspective on the display unit. For example, bending sensors running parallel to the user""s fingers, their bending radius changing due to the angle of bending of the respective finger, are incorporated into the control gloves. For example, the bending sensors may be implemented as variable resistors whose resistance changes as a function of the bending executed on the bending sensor. Such bending senors are also used in robotics for collision detection.
Another embodiment of bending sensors would be wire strain gauges which are used for measuring force in robotics, for example.
An object of the present invention was to create an inexpensive input device that can be used for mobile terminal devices in particular and will be easy to operate.
This object is achieved by the input device according to the present invention, where a bending sensor is connected to the longitudinal edge of a flexible wire.
In this case, only one-dimensional measurements are performed, i.e., only xe2x80x9cupxe2x80x9d or xe2x80x9cdown.xe2x80x9d Such an elongated input device may be attached to the mobile terminal and is easy to operate. A direction of movement is defined by specifying a preferential direction of bending of the flexible wire. For example, the displacement of a cursor in this direction of movement is determined by the bending radius and by the resistance of the bending sensor which changes as a function of the bending radius.
Two bending sensors are preferably arranged at a right angle to one another and connected to the longitudinal edges of the flexible wire, running parallel to one another along their longitudinal axes. The flexible wire should have a rectangular cross-section, so that the bending sensors can be attached better to the wire. In this way, the X axis would be defined by the first bending sensor and the Y axis would be defined by the second bending sensor. In this embodiment, the position is determined in a Cartesian coordinate system.
As an alternative, the flexible wire may be rotatably mounted on one end, with a sensor being provided to determine the angle of rotation of the flexible wire. In this embodiment, the displacement of a cursor is determined in the polar coordinate system. The distance of the cursor from the center point here is proportional to the deflection of the bending sensor. The coordinate angle is determined from the angle of rotation of the flexible wire.
The sensor for determining the angle of rotation may be a rotary position transducer, a pulse generator, a coding wheel or a similar device.
It is advantageous if the flexible wire is a spring wire so that it can automatically return to a zero position.
In addition, it is advantageous if at least one selector key is mounted on the free end of the flexible wire. Control signals for activating a command linked to a selected object, for example, can be triggered using this selector key.
One or more collector rings may be used to contact keys that might be provided for the case when an embodiment according to the present invention is used.
For example, the display unit may be a virtual retina display installed in a mobile terminal such as a mobile telephone. When using a mobile telephone, it is difficult to operate input devices provided on the mobile telephone while using the telephone. Due to the elongated input device, the point of action is shifted so far away from the mobile telephone that the input device can be operated easily and conveniently.